Epitaxial growth of GaAs films from elemental arsenic

Abstract

The metalorganic vapor phase epitaxial growth of GaAs has been investigated using trimethylgallium (TMGa) or triethylgallium (TEGa) and elemental arsenic (As) in hydrogen under atmospheric and reduced pressures. The important process parameters include the substrate temperature and the composition and flow rate of the reaction mixture. Device quality GaAs films have been grown at substrate temperatures of 450 °C or higher using TEGa and As, as compared with 510 °C or higher required by the TEGa-arsine process. The GaAs films deposited from TEGa and As are n-type, and the Hall mobilities in GaAs films deposited at 490 °C with a net electron concentration of 5×1015 cm−3 were 7000 and 23 000 cm2/V s at 300 and 77 K, respectively. The carbon concentration estimated from the 4.2 K photoluminescence measurements and the Hall mobility data is on the order of 5×1015 cm−3. Epitaxial GaAs films have also been grown from TMGa and As at 600 °C. These films are always p-type with room temperature net carrier concentration of 1015 cm−3 and higher and have higher carbon concentrations. Thus, the use of elemental arsenic for epitaxial growth of GaAs provides a cost-effective technology for many, particularly large area, GaAs devices.